1. Field of Invention
This invention relates generally to selecting operating conditions of an engine coupled to an electrical power generator for generating electrical power.
2. Description of Related Art
Advances in engine and hybrid vehicle technology have continually reduced harmful pollutant emissions. Hybrid vehicles having an engine driving a generator (a genset) cause emissions such as nitrogen oxides, carbon monoxide, hydrocarbons, and particulate matter. Each emission has a characteristic dependence on a power output level of the generator, and a rotational speed of the engine. Furthermore, given the present climate of higher prices of fossil fuels, there is a corresponding desire to reduce fuel consumption of the engine, thereby reducing the cost of operating the genset.
In particular, in electric hybrid vehicles, where the genset may supply electrical power to a drive motor and/or a charger for charging a storage battery, choosing operating points for the vehicle that minimize fuel consumption while simultaneously minimizing emissions or other operating conditions is a multi-variable problem and selecting operating points for the genset usually involves trading off between various emissions and fuel consumption to meet a desired criterion.
There remains a need for better methods and apparatus for selecting operating points of a genset, for use in hybrid vehicles and other applications.